[The adenovirus-mediated HSV-TK/GCV suicide gene system in the treatment of tongue carcinoma cell line].

OBJECTIVE: To study the effects of replication-defective recombinant adenovirus-mediated herpes simplex virus thymidine kinase (AdCMV HSV-TK)/ganciclovir (GCV) suicide gene system on tongue carcinoma cell line.

METHODS: Replication-defective recombinant adenovirus containing CMV promoter were propagated in 293 cells, purified by cesium chloride gradient and titrated by tissue culture infectious doses50 (TCID50) methods. Infectivity test was used to determine the efficiency of adenoviral transduction into tongue carcinoma cell line (Tca8113 cell line) and RT-PCR was applied to detect the expression of TK gene after infecting Tca8113 cells. The killing effects and bystander effects of HSV-TK/GCV system on tongue carcinoma cells were detected with MTT assay.

RESULTS: The adenoviral titration was about 2 x 10(10) plaque-forming units(PFU)/ml. The efficiency of adenoviral transduction into tongue carcinoma cells was more than 70 percent when multiplicity of infection (MOI) was more than 20. The recombinant adenovirus expressed TK gene after infecting Tca8113 cells in vitro. Adenovirus-mediated HSV-TK/GCV suicide gene system had killing effects on Tca8113 cells and these effects were related with time and GCV dose. The killing effects were poor after treated for 3 days and increased for 5 and 7 days. There had a good killing effect only when MOI was more than 20. When MOI was 80, GCV 5 x 10(-4) mol/L and treatment for 7 days, the viability of cells is only 4%. The bystander effect of this system on Tca8113 cells is poor.

CONCLUSIONS: Only when most of the tongue carcinoma cells were transferred by AdCMV HSV-TK, HSV-TK/GCV suicide gene system has good killing effect on tongue carcinoma cell line.